🚀 go-pugleaf

This should help a bit

int days = 0;

                while(startDate.get(Calendar.YEAR) !=
endDate.get(Calendar.YEAR) ||
                      startDate.get(Calendar.MONTH) !=
endDate.get(Calendar.MONTH) ||
                      startDate.get(Calendar.DATE) !=
endDate.get(Calendar.DATE) )
                {
                      startDate.add(Calendar.DATE, 1);
                      days++;
                }


Dag Welinder wrote:

> Hello!
>
> Is it possible to compute the number of days between two dates? I have
> two instances of GregorianCalendar, each containing a date. Can I
> compute the number of days between these two dates?
>
> Regards, Dag Welinder

On Thu, 30 Jul 1998, Dag Welinder <welinder@bigfoot.com> wrote:

> Is it possible to compute the number of days between two dates? I have
> two instances of GregorianCalendar, each containing a date. Can I
> compute the number of days between these two dates?

1) Get the long integer value from each of the dates (which
   represents the time in milliseconds since a fixed time, 1 Jan
   1970, I think, but it's not important).

2) Subtract the smaller from the larger number and you get the
   difference between the two dates in milliseconds.

3) Divide by 1000*60*60*24 (number of milliseconds in a day) to get
   number of days between the dates.

-- 
Marko Teittinen (marko@tekamah.com)   | Please don't send me any
Human-Computer Interaction Specialist | spam. My mail filter kills
Tekamah Corporation                   | all incoming ads anyway.

Try posing this message to the www.algorithms.org site

Dag Welinder wrote:

> Hello!
>
> Is it possible to compute the number of days between two dates? I have
> two instances of GregorianCalendar, each containing a date. Can I
> compute the number of days between these two dates?
>
> Regards, Dag Welinder

How about just doing a getTime() on the start and end and then divide the
difference by the number of milliseconds in a day?

This doesn't account for leap seconds, but I don't believe the Calendar
classes do either.

Ralph

In article <35C07780.DF0F02D4@bigfoot.com>,
  Dag Welinder <welinder@bigfoot.com> wrote:
> Hello!
>
> Is it possible to compute the number of days between two dates? I have
> two instances of GregorianCalendar, each containing a date. Can I
> compute the number of days between these two dates?

  Translate the dates to Julian numbers and subtract the two.

  // Quick and Dirty translation from an older
  // turbo pascal function
  // UNTESTED - see original funciton

  int Julian(int M, int D,int Y) {
    int j2; int ju;
    j2 = (M - 14) / 12;
    ju = D - 32075 + (1461 * (Y + 4800 + j2) / 4);
    ju = ju + (367 * (M - 2 - j2 * 12) / 12);
    ju = ju - (3 * ( (Y + 4900 + j2) / 100) / 4);

    return ju;
  }

  // original function
  function dateType.Julian( mo, da, yr: integer): LongInt;
  var     i, j, k, j2, ju: longInt;
  begin
       i := yr;     j := mo;     k := da;
       j2 := ( (j - 14) div 12 );
       ju := k - 32075 + (1461 * ( i + 4800 + j2 ) div 4 );
       ju := ju + ( 367 * (j - 2 - j2 * 12) div 12);
       ju := ju - (3 * ( (i + 4900 + j2) div 100) div 4);
       Julian := ju;
  end;  { Jul }



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Dag Welinder wrote:
> 
> Hello!
> 
> Is it possible to compute the number of days between two dates? I have
> two instances of GregorianCalendar, each containing a date. Can I
> compute the number of days between these two dates?
> 
> Regards, Dag Welinder

Get ACM's Collected Algorithm 199, recode it in Java (I did, took about
30 minutes), compute the Julian date for each end point, subtract the
two numbers, viola!
-- 
<------------------------------------------->
Allan Wax
e-mail:  Allan.Wax@jpl.nasa.gov
FAX:     + (213) 935-9292

NOTE: The views expressed in this message are
      my own and do not necessarily reflect
      those of my employer.

Why not use the built in method:
    int julian = myCalendar.get(Calendar.DAY_OF_YEAR);
Bill Scheidegger

Allan Wax wrote:

> Dag Welinder wrote:
> >
> > Hello!
> >
> > Is it possible to compute the number of days between two dates? I have
> > two instances of GregorianCalendar, each containing a date. Can I
> > compute the number of days between these two dates?
> >
> > Regards, Dag Welinder
>
> Get ACM's Collected Algorithm 199, recode it in Java (I did, took about
> 30 minutes), compute the Julian date for each end point, subtract the
> two numbers, viola!
> --
> <------------------------------------------->
> Allan Wax
> e-mail:  Allan.Wax@jpl.nasa.gov
> FAX:     + (213) 935-9292
>
> NOTE: The views expressed in this message are
>       my own and do not necessarily reflect
>       those of my employer.